A conventional tuning device for musical instruments, such as disclosed in U.S. Pat. No. 4,429,609 by Warrender, U.S. Pat. No. 4,457,203 by Schoenberg et al., U.S. Pat. No. 7,288,709 by Chiba and US 2006/0185499A1 by D'Addario et al., all hereby incorporated by reference, can measure one pitch frequency at a time and display the frequency deviation between the input signal and a target frequency. If a polyphonic signal, such as two pitch frequencies simultaneously, is fed to a conventional tuning device the display will typically be blank, indicating that no valid input was detected.
In many practical situations the musician does not hear the instrument while tuning, as this would be disturbing for an audience. Furthermore, the time to correct tuning of the instrument is often limited, as for instance in the break between songs in a performance. It is therefore important that the tuning device provides a user-friendly and appropriate output and works reliably and fast.
In order to tune an instrument like a guitar, which typically has six strings, each string must be plucked separately and the tuning must be adjusted until the deviation is sufficiently small.
In such a conventional tuning device verification of correct tuning requires that each string is plucked separately. This process is time-consuming.
Sometimes just one of six strings is out of tune, but in order to identify which string it is and subsequently correct the tuning each string must be checked. When using a conventional tuning device this checking process is of a serial nature, in that only one string at a time can be measured.
In many guitars adjusting the tuning of one string influences the tuning of the other strings. This is caused by the changed mechanical tension in the string being tuned, and therefore changed overall tension of the strings. As a guitar neck and body does posses some elasticity, tensioning one string will cause the tension of the other strings to be reduced slightly, due to bending of the neck and body, and thus potentially cause a need for re-tuning the other strings. A simultaneous display of the tuning of all six strings could be helpful when such a guitar is being tuned.
Some musical instrument tuners are generally applicable in that they have display means for indicating all 12 semitone names (from the chromatic scale). Such a tuner is commonly called “chromatic”. Notice that the pattern of 12 semitones repeats for each musical octave through the frequency (or pitch) range. In Western music the tone names are A, B, C, D, E, F, G plus an optional semi-tone step indicated by # or b (sharp or flat).
Other musical instrument tuners are specialised for instance for guitar use, such that only the tone names corresponding to the nominal values of the six strings: E, A, D, G, B, E, can be shown.
In general, conventional tuning devices do not require any modifications to the musical instrument in order to be usable.
The problem of tuning a guitar can also be solved using automatic means. An element of such a system is a measurement part, which by using one method or another, measures the tuning of each string. Such systems may work only for a single string at a time, whereas others may work on all strings simultaneously.
One such automatic tuning system is described in U.S. Pat. No. 4,803,908 by Skinn et al., where the sound signal for each string is measured separately by means of a pick-up for each string. So apart from the motors, gears, etc. needed to adjust the tuning automatically, the guitar must also be equipped with a special pick-up system.
In U.S. Pat. No. 4,375,180 by Scholz is described a system for automatic tuning of a guitar where the measurement of frequency is based on a mechanical measurement of the tension of each string, compared to a reference. That system is also dependent on a modification to a standard guitar, even for just the measurement part.
Another tuning device, in which frequency deviations for more than one string at time can be measured and displayed, is disclosed in U.S. Pat. No. 6,066,790 by Freeland et al., hereby incorporated by reference. This system can use a single channel pick-up, common for all strings, for measurement of all strings simultaneously. Hereby some disadvantages of the conventional tuning devices are reduced. However, according to the disclosure of U.S. Pat. No. 6,066,790, the same display format is used whether one or several strings are played at a time. If just a single string is being tuned only a small part of the display is used for showing relevant information. Moreover, the tuner disclosed in U.S. Pat. No. 6,066,790 is fixed with regard to the e.g. six frequency bands that are tied to a certain instrument type, e.g. a guitar, and the display configuration. Hence, the tuner only provides useful information for strings that are within a limited range of their correct tuning In other words, a chromatic tuner cannot be derived from the disclosure of U.S. Pat. No. 6,066,790.
It is an object of the present invention to provide a tuner that enables an unmodified guitar to be tuned easily by strumming/playing the strings simultaneously, and also facilitates precision tuning of individual strings.
It is an object of the present invention to provide a tuner with an improved visual output.
It is an object of the present invention to provide a tuner that enables simultaneous pitch frequency determination of several strings for a conventional guitar where a single audio channel is common for all six strings.
It is an object of the present invention to provide a tuner where the display shows sensible/usable information for most types of input signal, in particular monophonic and polyphonic signals.
A further problem related to the prior art is that this prior art is relatively difficult to operate due to the fact that such techniques are more suitable for skilled technicians rather than supporting the acting musician.